No abstract

Three Co(II)-malonate complexes, namely, (C(5)H(7)N(2))(4)[Co(C(3)H(2)O(4))(2)(H(2)O)(2)](NO(3))(2) (1), (C(5)H(7)N(2))(4)[Co(C(3)H(2)O(4))(2)(H(2)O)(2)](ClO(4))(2) (2), and (C(5)H(7)N(2))(4)[Co(C(3)H(2)O(4))(2)(H(2)O)(2)](PF(6))(2) (3) [C(5)H(7)N(2) = protonated 2-aminopyridine, C(3)H(4)O(4) = malonic acid, NO(3)(-) = nitrate, ClO(4)(-) = perchlorate, PF(6)(-) = hexafluorophosphate], have been synthesized from purely aqueous media, and their crystal structures have been determined by single crystal X-ray diffraction. A thorough analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions in 1-3, which are crucial in building supramolecular architectures. When these complexes are structurally compared with their previously reported analogous Ni(II) or Mg(II) compounds, a very interesting feature regarding the role of counteranions has emerged. This phenomenon can be best described as anion-induced formation of extended supramolecular networks of the type lone pair-π/π-π/π-anion-π/π-lone pair and lone pair-π/π-π/π-anion involving various weak forces like lone pair-π, π-π, and anion-π interactions. The strength of these π contacts has been estimated using DFT calculations (M06/6-31+G*), and the formation energy of the supramolecular networks has been also evaluated. The influence of the anion (NO(3)(-), ClO(4)(-), and PF(6)(-)) on the total interaction energy of the assembly is also studied.

No abstract

The novel non-covalent interactions between the charged and neutral aromatic rings and with anions are utilized to design the solid-state assembly of triply protonated PTPH 3 (PTP = 4'-(4-pyridyl)-3,2':6',3''-terpyridine) with H 2 O and three ClO 4 -, which is synthesized and characterized by single crystal X-ray diffraction analysis. Crystallography reveals that the π + -π + , π + -π and various anion···π interactions are the major driving forces in the stabilization of the selfassembled structure. In the title complex, a layered assembly is formed through the mutual influence of π + -π + and π + -π interactions. The anions are interacting with the charged π-acceptors which are again stabilized through π + -π interactions. So, the overall stabilization is governed through π + -π/π-π + , (π + -π + ) n and anion···π + /π + -π/π-π + networks in the solid state. The interaction energies of the main driving forces observed in the crystal structure have been calculated using density functional theory. In addition, the short O···O contact between ClO 4 -, anions has been analyzed in detail both computationally and exploring the Cambridge Structural Database.

Salt-bridge-p (sb-p) interactions at work: associative interactions of sb-p, p-p and anion-p in Cu(II)malonate-2-aminopyridine-hexafluoridophosphate ternary system3